Membrane potential

A voltage potential is a value representing the difference in electrical potential between two points. A membrane potential is the difference in electrical potential (in mV) between the outside and inside of a cell's membrane, on the intracellular side of the membrane based on the outside being zero.

Different types of cells have different resting membrane potentials. The resting membrane potential of neurons is -70 mV. During action potentials, the membrane potential changes drastically.

Figure 1. Cell resting membrane potential